The researchers found that higher baseline HOMA-IR and fasting insulin levels were independent predictors of poorer verbal fluency performance (P = 0.0002 for both) and of a greater decline in verbal fluency over follow-up (P = 0.004 for both). Word-list learning and word-list delayed recall scores were not predicted by baseline HOMA-IR or insulin. There were no interactions between cognitive test performance and HOMA-IR and apolipoprotein E ε4 genotype, hs-CRP, or type 2 diabetes. Baseline levels of fasting glucose and hs-CRP levels were not associated with cognitive functioning.

"Prevention and treatment of insulin resistance might help reduce cognitive decline later in life," the authors write.